VANCOUVER FIRE HALL ACHIEVES ZERO CARBON
Vancouver’s new Fire Hall 17 reflects the city’s design challenge to build a structure that meets the design certification requirements of the Canada Green Building Council’s Zero Carbon Building Program, one of 16 such pilot projects in Canada. The partners are also pursuing LEED Gold certification and, if approved, the building will be the first fire hall in North America to attain Passive House certification. These ambitious targets were set to align with City’s sustainability policies. According to HCMAArchitecture and Design, the building will reduce operational carbon emissions by 77 percent, compared with the fire hall it is replacing. The 19,375 sq ft (1800 m2) facility comprises four drive-through appa- ratus bays, accommodations for two firefighting crews and offices in the main building, and a six-story hose storage/training tower. Like all fire halls in Canada, the facility will serve as a post-disaster emergency hub, which requires a resilient building that can withstand seismic events. To meet the seismic requirements of Canada’s National Building code, the building has a stout reinforced concrete structure with a structural steel frame for portions of the third level. The main building is clad in brick and metal panels that cant outward at the base giving the form a strong and sturdy presence. Mitigating exterior and interior thermal bridging Central to meeting zero carbon goals is the building’s high-performance envelope, which wraps reinforced concrete walls with an 8 in. (20 cm) thick layer of mineral wool board having an R-value of 33, and an air barrier that allows a scant 0.6 of air change per hour at 50 Pascals of pressure. However, structural concrete and steel elements that penetrate the en- velope between the main building and tower, maintained at dissimilar temperatures, would allow the unabated passage of heat energy, absent a thermal bridging solution. “The fire hall has two thermal zones: the administrative offices and living spaces set 68˚F (20˚C), and the ground-level apparatus bay and training tower set to 50˚F (10˚C),” says Elise Woestyn, Passive House consultant with HCMA Architecture and Design. The struc- tures share a concrete frame at ground level, and are connected by combinations of steel frame and concrete bridges on levels two and CERTIFICATION, INCORPORATES STRUCTURAL THERMAL BREAKS City of Vancouver sets aggressive environmental goals for the new facility
three, and a steel frame at level four. Due to the temperature differ- ences, the designers needed to thermally isolate the two zones, while maintaining structural continuity. “Our need to address thermal bridging led us to structural thermal breaks,” says Federica Piccone, architect with HCMA Architecture and Design. At the connection points, the design team specified Isokorb® concrete- to-concrete and concrete-to-steel structural thermal breaks fromSchöck North America. Each concrete-to-concrete module consists of a rigid foam block penetrated by stainless steel rebar that is tied into rebar on both sides of the slab or wall before concrete is poured conventionally. Each concrete-to-steel structural thermal break includes stainless steel rebar projecting from one side of the module that ties into rebar of the interior slab, and stainless steel threaded rod projecting from the opposite side of the module that bolts to exterior steel beam flanges. Three concrete balconies also project from the tower’s facade. Con- crete-to-concrete thermal breaks were installed between each balcony and interior slab to mitigate thermal bridging, while withstanding the rotational and shear forces created by these cantilevers.
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july 2021
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